Deep folder structure potential fix

Ok, so i've created a potential fix for this issue. The main change is that `Open-Include.sublime-settings` needs to be tweaked in order to allow all kind of extensionless files:

```json
    "auto_extension" : [
      {
        "extension": ".scss",
        "prefix"   : "_"
      },
      {
        "extension": ".sass",
        "prefix"   : "_"
      }
    ]
```

I tested and works in:

1. sass/scss files (with partials and no extensions)
1. html script src=""
1. html/htaccss SSI `<!--#include virtual="includes/partials/sidebar/sideNav.html" -->`
1. grunt configs

I never used other files that are potentially extension-less (hbs, coffee, jade etc) so any tests from users would be awesome :)